Fix a warning in libvpxJNI
Fix a warning in libvpxJNI

v2/extensions/vp9/src/main/jni/vpx_jni.cc:63:31: warning: missing field 'w' initializer [-Wmissing-field-initializers]
  vpx_codec_dec_cfg_t cfg = {0};
                              ^

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=132461351

androidx/media,YouKim/ExoPlayer,jeoliva/ExoPlayer,michalliu/ExoPlayer,Ood-Tsen/ExoPlayer,YouKim/ExoPlayer,jeoliva/ExoPlayer,google/ExoPlayer,barbarian/ExoPlayer,KiminRyu/ExoPlayer,saki4510t/ExoPlayer,superbderrick/ExoPlayer,jcable/ExoPlayer,yangwuan55/ExoPlayer,KiminRyu/ExoPlayer,michalliu/ExoPlayer,kiall/ExoPlayer,fanhattan/ExoPlayer,fanhattan/ExoPlayer,zhouweiguo2017/ExoPlayer,WeiChungChang/ExoPlayer,kiall/ExoPlayer,jcable/ExoPlayer,yangwuan55/ExoPlayer,ebr11/ExoPlayer,androidx/media,ened/ExoPlayer,rubensousa/exoplayer-amazon-port,ebr11/ExoPlayer,rubensousa/exoplayer-amazon-port,rubensousa/exoplayer-amazon-port,MaTriXy/ExoPlayer,Ood-Tsen/ExoPlayer,zhouweiguo2017/ExoPlayer,google/ExoPlayer,ClubCom/AndroidExoPlayer,MaTriXy/ExoPlayer,ClubCom/AndroidExoPlayer,superbderrick/ExoPlayer,google/ExoPlayer,androidx/media,jcable/ExoPlayer,WeiChungChang/ExoPlayer,WeiChungChang/ExoPlayer,saki4510t/ExoPlayer,JasonFengHot/ExoPlayerSource,yangwuan55/ExoPlayer,jeoliva/ExoPlayer,tntcrowd/ExoPlayer,ened/ExoPlayer,stari4ek/ExoPlayer,JasonFengHot/ExoPlayerSource,kiall/ExoPlayer,michalliu/ExoPlayer,amzn/exoplayer-amazon-port,zhouweiguo2017/ExoPlayer,amzn/exoplayer-amazon-port,YouKim/ExoPlayer,fanhattan/ExoPlayer,MaTriXy/ExoPlayer,stari4ek/ExoPlayer,tntcrowd/ExoPlayer,tntcrowd/ExoPlayer,barbarian/ExoPlayer,JasonFengHot/ExoPlayerSource,superbderrick/ExoPlayer,YouKim/ExoPlayer,saki4510t/ExoPlayer,Ood-Tsen/ExoPlayer,ebr11/ExoPlayer,barbarian/ExoPlayer,KiminRyu/ExoPlayer,amzn/exoplayer-amazon-port,stari4ek/ExoPlayer,ClubCom/AndroidExoPlayer,ened/ExoPlayer